Safety arrangements for liquid fuel burning devices



March 17, 1970 A. w. RICHARDSON 3,501,252

SAFETY ARRANGEMENTS FOR LIQUID FUEL BURNING DEVICES Filed Dec. 4, 1967 xmm United States Patent US. Cl. 43133 6 Claims ABSTRACT OF THE DISCLOSURE A liquid fuel burning appliance in which provision is made for applying pressure to a flame extinguishing medium in response to abnormal conditions of the appliance to discharge the medium into the burner.

DESCRIPTION OF INVENTION The invention relates to liquid fuel burning devices, for example, domestic space heaters, for which are employed fuels such as hydro-carbons, usually kerosine or paraffin, alcoholic fuels, and mixtures thereof.

Devices of this kind can be dangerous in certain circumstances in particular if they are overturned or tilted through a large angle whilst alight because the flame might spread outside the burner and ignite any fuel that has escaped. Against this danger, steps can be taken to prevent or reduce leakage of fuel as disclosed for example in my US. Letters Patent No. 3,316,956. Arrangements can also be made to extinguish the flame when the device is tilted through more than a predetermined angle, as described in my US. Letters Patent No. 3,420,612. An object of the present invention is to provide improved arrangements of this type.

My Patent 3,420,612 relates to a liquid fuel burner or burning appliance having a container for a fuel extinguishing material, the container having outlet means positioned to discharge the material into the combustion zone to extinguish the flame on tilting of the appliance from a normal position through more than a predetermined angle. The present invention provides such an appliance in which the flame extinguishing material is discharged under pressure. The invention also provides arrangements for extinguishing burners under other conditions which make this necessary or desirable, for example, when too high a temperature is reached in or near the burner or when too much soot is being formed. Extinction of the burner flame can be effected in any suitable way, as by material supported under gravity or pressure.

The invention accordingly consists in a liquid fuel burner in combination with flame extinguishing means comprising a container for a flame extinguishing medium mounted in fixed relation to the burner, at least one conduit tube leading from the container to the burner and means for discharging said medium along said conduit into the burner.

Various means may be employed for discharging the medium under pressure, for example a piston in combination with energy storage means, such as a coiled spring, or a releasable compressed gas capsule.

The extinguishing medium may be a liquid, a powder or a gas. In a preferred embodiment where the extinguishing medium is a liquid the piston operates in a main container to force the liquid out of a series connected auxiliary container into the conduit. Preferably, and especially where the extinguishing medium is a powder, the container is situated above the level of the burner so that gravitational force assists in the discharge of the medium downwardly through the conduit.

Patented Mar. 17, 1970 In an advantageous embodiment the extinguishing medium is evolved by chemical reaction. Such media are already known in portable fire extinguishing appliances wherein chemical substances are brought into contact with each other to evolve by reaction an extinguishing fluid. The reaction may be such as to provide the discharge pressure, or the pressure generated by the reaction may be supplemented by mechanical pressure, resulting from an energy storage device, e.g. a spring held under compression.

The material can be arranged to be discharged from a container, whether by means of a spring loaded piston or any other energy'storage device, on the tilting of the appliance out of the vertical, or on the occurrence of certain abnormal operating conditions. A mechanical arrangement can be readily reset but the necessary pressure can be provided by other than mechanical means, for example, by expendible compressed gas capsules.

In an embodiment particularly suitable for liquid or powder media the containing means for the extinguishing medium are located above the level of the fuel burner, and the conduit enters the burner at a position below the level of the liquid fuel in the burner whilst the conduit tube leading to the burner terminates at its lower end in a plurality of branches extending upwardly above the level of the liquid fuel in the burner.

Where a portable appliance is required to be proof against disturbance it will include a locking device for normally disabling the medium discharge means, said locking device being automatically releasable by means responsive to an abnormal condition of the burner. For axample the locking device may include a support rod for maintaining the casing in equilibrium, and a spring loaded latch engaging said rod whereby the latch is released upon the equilibrium of the casing being disturbed.

Alternatively, or in addition, the release means for the locking device may comprise a thermally responsive element.

' Furthermore, a release means for the locking device may comprise a photo-electric cell arranged to be obscured by soot formation resulting from abnormal flame conditions in the burner.

The portable appliance preferably also includes manually operable means for retaining the locking device in the locking condition when lifting or transporting the casing. Such means may embody or be combined with a carrying handle.

By way of example, a domestic space heater incorporting the invention is described below with reference to the accompanying drawing.

In this embodiment of the invention, the heater is provided with flame extinguishing means and a release mechanism which comprises a vertical support rod 2 mounted for longitudinal sliding at the rear of the heater. The lower end of the rod engages .the floor on which the heater stands and the upper end normally supports an arm 1 to hold this horizontal. The arm 1 can pivot to a vertical position, shown in chain lines, when the rod 2 drops on disengagement of its lower end from the floor on tilting or lifting of the heater.

Also provided is a container for the fluent flame extinguishing material, in the form of a cylinder 5 mounted on the rear wall of the casing 9 of the heater, with its axis vertical. A piston rod 3 extending through the upper wall of the cylinder carries at its lower end a piston 4 which slidingly engages the cylinder wall. At the upper end of the piston rod 3, a lateral projection 3a normally engages the top of the arm 1 of the release mechanism so that the piston rod 4 is held in an elevated position within the cylinder against the action of a compression spring 4a acting between the piston and the cylinder top wall. As soon as the arm 1 is no longer held horizontal,

the piston rod 3 is released and the spring acts to urge the piston downwardly within the cylinder.

Where the extinguishing medium is a fluid, the means for delivering the medium can comprise a series connection provided at the base of the cylinder 5 to the interior of an adjacent auxiliary cylinder, which can be of smaller volume. The connection may be at the base of the auxiliary cylinder 11, and at the top of the cylinder 11 a port 6 leads through a conduit tube 7 having discharge ends suitably positioned with respect to the combustion zone of the heater. The cylinders 5 and 11 are conveniently mounted above the liquid fuel level and about half-way up the heater, and the tube 7 then extends forwardly and downwardly to below the level of the liquid level in the burner. The burner may be of the known short drum type, having concentric perforated burner shells (not shown) supported on a trough 8. At this level, the tube 7 divides into two or three upright portions 12 having discharge ends within and slightly above the level of the trough, though the discharge ends could equally be in the floor of the trough or just above the combustion zone.

Both containers 5 and 11 normally contain a flame extinguishing liquid, which can be introduced through a removable cap at the top of the cylinder 11. On upsetting of the appliance, the spring pushes the rod 2 down to release the plunger 3, and the spring urges the piston 4 downwardly, so sweeping the liquid in the cylinders, through the outlet 6 and tube 7. The liquid discharges from the open ends of the upright tube portions 12 and extinguishes the flame.

The invention can employ any suitable release mechanism, which can be arranged to be responsive only to tilting or to both tilting and lifting if desired. The support rod 2 may be so arranged that, instead of having rectilinear sliding motion, it can rock about a fixed pivot (not shown) intermediate its ends in a plane transverse to the latch arm 1.

The appliance is stable when in a vertical position with the latch arm 1 bearing on the top end of the rod 2. When the appliance is tilted, its weight will force the rod to turn about the pivot and release the latch arm 1. The apparatus described is suitable for use with any fluid extinguishing material but the invention can employ any fluent material, for example, a powder. If the powder is insufficiently fluid to flow from the base of a container except under the pressure of the piston, the auxiliary cylinder 11 must be dispensed with. Instead of using an auxiliary cylinder, a tube from the base of the container 5 can, if necessary, be extended upwardly to a level higher than that of the liquid in the container before descending to the burner in cases where the extinguishing medium is a gas or liquid. It is in any event better to apply pressure to the fluid material downwardly, because of the otherwise disadvantageous effect of friction on the piston. The auxiliary cylinder can also be dispensed with by positioning the container 5 so that the liquid level within it is below the level of the tube discharge ends. However, it is advantageous to have the container high enough to function if the heater is tipped over, even if the pressure falls. Thus, a linked spring loaded system such as that shown in the drawing arranged at any level with respect to the 'burner, can operate to pressurize the fluid material in the container on tipping or complete upsetting of the appliance.

In any event, irrespective of the position of the container 5 with respect to the burner, the extinguishing medium may be evolved by chemical reaction of the kind employed in known types of portable fire extinguishers. For example a capsule or diaphragm may be arranged to be ruptured or pierced by the action of the piston 4.

To enable the arrangement described to be rendered inoperable when the heater is simply lifted, a suitable locking means may be provided. Such a locking means can be put into effect by operation of a special control knob or handle or can be automatically operative when the heater is lifted by a handle provided. Thus, a retractable handle can be provided at the top of the heater and this can be connected to the rod 2 by a lostmotion action such that when the handle is in its lowered position, the rod is free to drop but when the handle is drawn fully for use, the rod 2 is held in its upper position. For example the handle, or a part thereof may be slidable on a vertical slot parallel to the piston rod 3 and terminating just below the latch arm 1 when horizontal. The handle may also be linked to the rod 2. Whatever the form of locking arrangement an indicator means is preferably provided so that the user can readily see whether or not the safety arrangements are in effect; such locking and indicator means can also be applied to other mechanical snufling devices.

Besides or alternative to the arrangements described, there could be employed in accordance with the invention, a temperature responsive means in the vicinity of the burner, for example a pressure capsule or bimetallic strip, for triggering or releasing an energy storage device for actuating and/or pressurizing a container for fluent fire extinguishing material. A further control arrangement, particularly applicable to a wick convector, within the scope of the invention includes a photo-electric cell responsive to an abnormal flame condition, for example the obscuring effect of soot formation. Such a cell can be associated with a fine gauze of a gauge that passes fine carbon particles but collects those of the size which amount to visible sooting.

It will be evident that the invention can be embodied in a variety of ways to provide prompt and effective extinguishing arrangements applicable to any form of liquid fuel burning device.

I claim:

1. A liquid fuel burner in combination with flame extinguishing means comprising a container mounted in fixed relation to the burner, a flame extinguishing medium in said container, at least one conduit tube leading from the container to the burner, a piston held in a locked position under pressure and means for releasing said piston to discharge said medium under pressure along said conduit.

2. A liquid fuel burner as claimed in claim 1, wherein the piston is actuated by gas under pressure.

3. A liquid fuel burner in combination with flame extinguishing means comprising a container for a liquid flame extinguishing medium mounted in fixed relation to the burner, at least one conduit tube leading from the container to the burner, and pressure applying means responsive to an abnormal condition of the burner to apply pressure directly on said medium to discharge said medium along said conduit into the burner.

4. A liquid fuel burner as claimed in claim 3, wherein the container comprises two chambers interconnected at their lower end and adapted to contain a liquid medium, the outlet from said container to said conduit tube being adjacent the upper end of one of said chambers, and the pressure applying means being adapted to apply pressure directly on said liquid medium adjacent the upper end of the other of said chambers.

5. A liquid fuel burner in combination with flame extinguishing means comprising a container mounted in fixed relation to the burner, a flame extinguishing medium in said container, at least one conduit tube leading from the container to the burner, a pressure storage device, and pressure releasing means for said pressure storage device, said means being normally disabled, and automatically enabled in response to an abnormal condition of the burner to release the pressure in said pressure storage device to act directly on said medium to discharge said medium under pressure along said conduit.

6. A liquid fuel burner in combination with flame extinguishing means comprising a container for a flame extinguishing medium mounted in fixed relation to the burner, at least one conduit tube leading from the con tainer to the burner, a pressure applying device capable of 380,885 4/1888 Greene 43133 applying pressure directly to said extinguishing medium, 815,215 3/1906 Richardson 431-33 and locking means for normally disabling said pressure 2,753,926 7/1956 Beach 431-445 X applying device, said locking means being responsive to 3,342,174 9/1967 Tongue et a1. 12696 an abnormal condition of the burner to enable said pres- 5 sure applying device. FREDERICK L. MATTESON, JR., Primary Examiner References Cited R. A. DUA, Assistant Examiner UNITED STATES PATENTS CL 82,590 9/1868 Boydston 431 33 10 4 -8 5 358,658 3/1887 Hall "431-145 

